Characterization of surface roughness by speckle pattern—an experimental approach

Abstract

Abstract Although it originates from the ancient Greeks, optics still arouses a lot of scientific interest, mainly due to the technological innovation associated with it. One of its most interesting applications is related to optical metrology and the characterization of materials through optical techniques. While some of these processes can be explained in a simplified way using a few of the fundamental principles of physics, there are hardly any proposals whose objective is to discuss this topic at a basic level. Accordingly, we present a low-cost experiment that allows the characterization of surface roughness using the fractal dimension of the speckle pattern associated with the light scattered by a surface. For simplicity, the entire activity is adaptable to the most diverse school situations. Moreover, it allows the discussion of many fundamental physics concepts and provides students with an experience similar to that experienced by scientists.